The present invention relates to a golf ball which has an excellent rebound and good manufacturability.
Efforts to impart golf balls with an excellent rebound have until now focused on one or more indicator of the polybutadiene used as the base rubber, such as the Mooney viscosity, polymerization catalyst, solvent viscosity and molecular weight distribution, and attempted to optimize these indicators. See, for example, Patent Document 1: JP-A 2004-292667; Patent Document 2: U.S. Pat. No. 6,818,705; Patent Document 3: JP-A 2002-355336; Patent Document 4: JP-A 2002-355337; Patent Document 5: JP-A 2002-355338; Patent Document 6: JP-A 2002-355339; Patent Document 7: JP-A 2002-355340; and Patent Document 8: JP-A 2002-356581.
For example, Patent Document 1 (JP-A 2004-292667) describes, as a base rubber for golf balls, a polybutadiene having a Mooney viscosity of 30 to 42 and a molecular weight distribution (Mw/Mn) of 2.5 to 3.8. Patent Document 2 (U.S. Pat. No. 6,818,705) describes, for the same purpose, a polybutadiene having a molecular weight of at least 200,000 and a resilience index of at least 40.
However, many golfers desire golf balls capable of attaining a longer travel distance, and so a need exists for the development of golf balls having an even better rebound.
Obtaining a golf ball having a high rebound has required until now the use of a high Mooney viscosity rubber, which has a poor workability and inevitably lowers the manufacturability of the ball. A desire has thus existed for the development of a high-rebound golf ball without reducing the ease of manufacture.